3406B head spacer plate

I get some from ATL Diesel and haven’t had any problems out of them.

if you need the thinner one CAT was the only source last time I needed one a couple years ago. ATL would tell me they had the thinner one and send me the thick one saying the thinner one updated to the the thicker one. Tony down at Riggs fixed that pretty quickly

 

When counterboring a block yes you set protrusion off the shims and always run the thicker plate. But if you have an engine with low liners across the board with say 500k or less on it and you don’t really want to do a major you can get by with the thin plate

 

No there is 1 spacer plate gasket and 1 head gasket

 

Also comes in handy when the shop owner's know it all punk son goes too deep doing the counterbores and comes back a week later with a blown head gasket.

Yeah, it happened.